This application to PA-14-190 (Epidemiology and Prevention in Alcohol Research (R01)) continues research to reduce college students' alcohol use and consequences (R01AA012547; Larimer PI). Development of efficacious college drinking interventions is an important public health priority. Personalized feedback interventions (PFI), delivered via mail, internet, cell-phone, and text messaging, have evidence of efficacy but effects are small and variable across time and outcomes. Remote PFI delivery increases reach, but introduces barriers to efficacy, particularly variable attention to and comprehension of material. PFIs with multiple components delivered simultaneously may be overwhelming or confusing. This is problematic, as highly personalized feedback interventions with more components may produce larger and longer effects. In contrast, short-term efficacy of single-component PFIs (e.g., normative feedback) has been established, and these simpler PFIs may have more immediate impact; however, duration has been variable. Research is needed to determine optimal delivery to capitalize on clarity and initial impact of single-component and greater effect size and duration of multi-component PFIs. Duration may also be impacted by fluctuations in drinking during high- risk events. Moreover, PFI effects may be attenuated by timing of assessments relative to important high-risk events (e.g., New Year's eve falling within assessment of past month drinking), as well as time elapsed between PFI and specific events and if the PFI addressed the high-risk event. Providing boosters to address high-risk events, assessing drinking during these events and on typical occasions, and evaluating impact of intervention and assessment timing relative to high-risk events may help explain inconsistent findings regarding PFI effect size and duration. The current study addresses these gaps through evaluating a multi- component online PFI with simultaneous delivery (all PFI components at once) versus a sequential format, wherein individual PFI components are delivered one at a time to minimize attention demands for each component. The study seeks to enhance magnitude and duration of effects through adding text-message- based boosters to address specific high-risk events during the year following intervention. We will assess event-specific and typical drinking and consequences to evaluate immediate and sustained (through 24 months) changes in mediators and outcomes. Participants (N=1000 heavy drinking students) will be recruited in 4 cohorts corresponding with each quarter of the calendar year, and randomly assigned in a 2 (simultaneous versus sequential PFI) x 2 (boosters or no boosters) +1 (Assessment Only Control) longitudinal RCT design. Specific aims are: 1)Evaluate efficacy, moderators, and mediators of multi-component PFI, comparing simultaneous vs. sequential delivery vs. AOC; 2) Evaluate impact, mediators, and moderators of event-specific boosters on outcomes for both typical and event-specific drinking; 3) Evaluate timing of high-risk events relative to time since initial PFI and timing of longitudinal follow-up assessments on intervention efficacy.